The flank surfaces of spiral bevel gear teeth are typically finish machined on a gear generating machine by a rotary milling cutter. An example of a gear generating machine is illustrated in U.S. Pat. No. 5,133,627 which issued to C. E. Lindsey on Jul. 28, 1992. The rotary milling cutter has its tooth cutters arranged only part-way around its periphery with a gap between the last and first tooth blades. The finish-cutting operation is effected by rotating the milling cutter continuously, holding the gear blank stationary while the blades of the cutter pass through the valley or space between adjacent gear teeth and indexing the gear blank when the gap in the cutter is abreast of the gear blank. The indexing operation must be timed very closely to the rotation of the cutter and the gear blank must be positioned very accurately on the workpiece spindle so that the blades of the cutter will enter the space between the teeth and remove preselected portions of material from the teeth.
Orientation of the tooth cutters of the milling cutter to the rough cut teeth and specifically the space between the teeth is critical since only a small amount of material is generally removed during the finish operation. Considerable time and effort is required to establish the initial position of the gear blank on a workpiece spindle of the gear generating machine at the time of initial "set up". A gear blank is mounted on the workpiece spindle leaving a workpiece chuck unclamped whereupon the gear blank is slowly moved into the tooth cutters with the tooth cutters being centered as best as possible in the space between adjacent gear teeth. To effect this centering, the gear blank is repeatedly rotated slightly on the work piece spindle until the cutter blades are preferably centered in the space between the gear teeth and generally equal amount of material is removed from each tooth flank. Typically twenty to thirty minutes may be required to precisely center the cutter blades in the space resulting in increased customer cost and greater possibility of cutter or piece part damage.
A stock divider device is then used to duplicate the position for succeeding gear blanks on the workpiece spindle after the relative position of the cutting blades to the rotary cutter has been established. Stock dividing devices have balls or fingers which are adapted to engage opposed tooth flank surfaces of the teeth. Examples of such devices are shown in U.S. Pat. No. 2,139,154 which issued to C. T. Galloway on Dec. 6, 1938 and U.S. Pat. No. 3,368,455 which issued on Feb. 13, 1968 to C. G. Ellwanger.
Accordingly, what is needed is an apparatus to quickly, easily, and precisely initially orientate the cutter blades of a milling cutter relative to rough cut teeth of a gear blank. The subject invention provides this function and represents a savings of equipment, labor, and natural resources.
The present invention is directed to overcome one or more of the problems as set forth above.